Replacing brake chamber

Discussion in 'Trucks [ Eighteen Wheelers ]' started by mitmaks, Mar 13, 2020.

  1. Dino soar

    Dino soar Road Train Member

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    I just looked at your photos again and I think those are the Meritor type slack adjusters.

    I don't know if they have a different type of procedure I use the other haldex type slack adjusters.

    Listen to whatever @spsauerland tells you.

    Whatever he says is correct.
     
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  3. AModelCat

    AModelCat Road Train Member

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    One word of advice, make sure you get the proper clevis for the Rockwell slacks. Wrong spacing between the pins and they will not adjust properly. I speak from experience.
     
  4. zaroba

    zaroba Heavy Load Member

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    Had to replace one of mine, think the exact same style slack adjusters except for that yellow thing underneath in those pictures.

    Pulled off the old chamber and sat it next to the new one to mark where to cut and used a hacksaw that I picked up at Lowes, then installed the new one. Bolted it into the bracket then attached the thingy at the end. Assuming they are exactly the same, my trailers slack adjusters have a torx head nut on top of them that was easy to turn with a hex socket to manually move the slack adjuster, made it really easy to reattach the pushrod. Probably wasn't the proper way to do everything but it worked.

    20200528_100040.jpg

    Would have worked fine if I could have reused the end piece that attaches to the slack adjuster, but the rear pin was too corroded to remove and the piece fell out of the adjuster. Ended up having to use a smaller connector that came with the chamber, rendering the rod an inch or two on the short side and I guess it no longer automatically adjusts. But it has passed 2 inspections so far.
    (Brakes released in this pic)
    20200829_181026.jpg
     
    Last edited: Aug 29, 2020
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  5. AModelCat

    AModelCat Road Train Member

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    I hated changing out the whole chamber. If possible I just swapped out the spring chamber.
     
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  6. spsauerland

    spsauerland Road Train Member

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    That will not self-adjust.
     
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  7. spsauerland

    spsauerland Road Train Member

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  8. drive-away2020

    drive-away2020 Light Load Member

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    47774616-79B6-46EB-99B8-8C0E737CC6D2.jpeg Thanks y’all! I seem to have got all 4 back in adjustment. They move about 1” with full brake application. The picture above is with a brake application.

    They were to long. I did pretty much the same exact thing @Dino soar said to do. Measure square with the S-cam, then measure back 2.5 inches for axle one, and 2.25 inches for axle two. They have different slacks, two of the same on each axle, but different from axle to axle. Which is weird because last time I did slacks I did all 4 at once so I thought... hmm... but how I got the 2.5 and 2.25 number was from measuring from center S-cam to center main clevis, then going by the chart to see how far to measure back.

    I measured and cut all 4 of them with the angle grinder. Put anti seize on the clevis’, used the new anti-seize $5 cotter pins (pretty cool invention) , adjusted back the brakes, did about 12 full brake applications, took measurement (with the new brake safe method, such a convenient invention!) and everything is holding its adjustment and well in spec.

    thanks!!!!
     
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  9. Shawn2130

    Shawn2130 Heavy Load Member

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    I actually don’t mind changing out the whole chamber.

    The no pressure side mount will eventually rot out and need replacing.

    I use a template that comes with any new slack adjuster and save them for future reference for when I need to replace the whole chamber.

    We use, meritor, Gunite, Haldex styles.

    I would mount the new chamber on, spin on the nut, hold the clevis, use the template as a guide, spin the nut to where the clevis is.

    Mark the spot to cut which leaves about 3/4 inch or so of threaded rod for the clevis to thread on.

    Then assemble the clevis, pin to slack adjuster.
     
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  10. drive-away2020

    drive-away2020 Light Load Member

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    F2C27DA6-DA8E-4197-913E-19E408811FB4.jpeg BBC52A63-0AB3-4AFB-84AD-AB121F84C817.jpeg B991A299-8867-4CA8-9B57-D958F3D152B0.jpeg These are what those anti seize cotter pins look like. I’m not sure if y’all seen them yet before? They’re about $5 each, but I like them! They allow the clevis pin to roll in a brake application, virtually keeping them from ever seizing. Something about the clevis rolling allows the slacks to adjust better too.

    they’re made by the same company as brake safe, which is Spectra Products from Canada. But they don’t have a direct way to buy the cotter pins. They have a couple of American vendors for it though if interested
     
    Last edited: Aug 31, 2020
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